The estimation of Adonis vernalis populations in chosen patches of Lublin Upland

Abstract

The number of Adonis vernalis populations, their size and abundance in xerothermic communities of the Lublin Upland have decreased significantly in the last 40-50 years, which indicates that there is a real risk of species extinction in the studied area. The paper is an attempt to indicate the possible factors which influence the decrease of Adonis vernalis populations. Detailed studies were carried out in six sites differing habitat conditions, land use and the size of Adonis vernalis populations. Observations were made of the abundance of blooming and the number of anthers per flower. The ability for reproduction was estimated indirectly by the mass of pollen delivered and its biological value. The populations of Adonis vernalis differ in number of anthers per flower (94.4 - 131.5, on average), the mass of pollen delivered (0.83 mg - 3.18 mg per 100 anthers, on average), the biological value of pollen and the size of pollen grains. Generally, stronger populations were characterized by better quality and a higher quantity of pollen. Potential energy of pollen in flowers from Pliszczyn and Łabunie was 69-72%, compared to 36%-47% in the remaining populations. Grass burning did not cause a reduction of potential biological value of Adonis vernalis pollen. Xerothermic swards in Pliszczyn and Kąty regularly burnt developed strong, most abundant populations of Adonis vernalis with favorable pollen. The development of the shrub layer, if it is out of control, stands in the way of satisfactory reproduction of halophilous Adonis vernalis.